water soluble

Vitamin A

• Overview: First fat-soluble vitamin, essential for vision.

• Eye Health:

  • Maintains a healthy cornea, keeping it moist.

  • Involved in light perception; deficiency can cause night blindness.

  • Severe deficiency can lead to keratinization, resulting in blindness.

• Prevalence of Deficiency:

  • Global issue: 3-10 million children suffer from severe vitamin A deficiency.

  • Mild deficiency can impair immune function and stunt growth.

• Food Sources:

  • Animal Sources: Retinol (active form of Vitamin A) found in liver, milk, and eggs.

  • Plant Sources: Beta-carotene (provitamin A) from carrots, sweet potatoes, and dark leafy greens.

  • Toxicity: High doses, especially from supplements, can harm pregnant women by causing birth defects.

• Beta-Carotene vs. Retinol:

  • Beta-carotene is converted into retinol in the liver; cannot cause toxicity due to controlled conversion.

  • Excessive beta-carotene can temporarily discolor skin but is not harmful.

• Antioxidant Properties:

  • Beta-carotene can block free radicals, reducing DNA damage and cancer risk.

Vitamin D

• Overview: Also known as the sunshine vitamin; fat-soluble.

• Function:

  • Essential for calcium absorption, vital for bone health.

  • Deficiency leads to rickets in children or osteomalacia in adults.

• Synthesis:

  • Skin synthesizes vitamin D upon UV exposure; factors affecting synthesis include skin color, clothing, pollution, and sunblock.

• Dietary Sources:

  • Found in fatty foods like fish, egg yolks, fortified milk, and cereals.

  • Supplement recommendations usually around 1000 IUs; check with a doctor for blood levels.

Vitamin E

• Overview: Fat-soluble vitamin known as the "extraordinary bodyguard" due to its antioxidant properties.

• Functions:

  • Protects cells from free radical damage and may reduce risks of cancer and heart disease.

• Food Sources:

  • Found in vegetable oils, nuts, seeds, and whole grains.

  • Low intake in the U.S.; often destroyed in processed or fried foods.

Vitamin K

• Overview: Fat-soluble vitamin involved in blood clotting and bone formation.

• Sources:

  • Primarily found in leafy green vegetables (e.g., kale, broccoli), also in canola and soybean oils.

  • Synthesized by gut bacteria; newborns are given vitamin K injections to prevent bleeding issues.

Vitamin C (Water-Soluble)

• Functions:

  • Required for collagen synthesis and maintaining connective tissues.

  • Acts as an antioxidant to prevent free radical damage; supports immune function.

• Deficiency:

  • Severe deficiency leads to scurvy, characterized by bleeding gums and weakened collagen structures.

• Food Sources:

  • High in citrus fruits, peppers, berries, tomatoes, and broccoli.

• Recommended Intake:

  • Smokers need higher amounts (~125 mg) due to increased free radical exposure; nonsmokers require about 90 mg.

• Toxicity:

  • Low risk; excess vitamin C is excreted, but high doses may cause gastrointestinal disturbances.